Merge "Add HLG transfer function to proper dataspace" into tm-dev (ff986fe4) · Commits · e / os / android_frameworks_base

libs/hwui/utils/Color.cpp

+25 −1

Original line number	Diff line number	Diff line
		@@ -165,6 +165,14 @@ android_dataspace ColorSpaceToADataSpace(SkColorSpace* colorSpace, SkColorType c
		if (SkColorSpace::Equals(colorSpace, rec2020PQ.get())) {
		return HAL_DATASPACE_BT2020_PQ;
		}
		// HLG
		const auto hlgFn = GetHLGScaleTransferFunction();
		if (hlgFn.has_value()) {
		auto rec2020HLG = SkColorSpace::MakeRGB(hlgFn.value(), SkNamedGamut::kRec2020);
		if (SkColorSpace::Equals(colorSpace, rec2020HLG.get())) {
		return static_cast<android_dataspace>(HAL_DATASPACE_BT2020_HLG);
		}
		}
		LOG_ALWAYS_FATAL("Only select non-numerical transfer functions are supported");
		}

		@@ -247,6 +255,14 @@ sk_sp<SkColorSpace> DataSpaceToColorSpace(android_dataspace dataspace) {
		return nullptr;
		}

		// HLG
		if ((dataspace & HAL_DATASPACE_TRANSFER_MASK) == HAL_DATASPACE_TRANSFER_HLG) {
		const auto hlgFn = GetHLGScaleTransferFunction();
		if (hlgFn.has_value()) {
		return SkColorSpace::MakeRGB(hlgFn.value(), gamut);
		}
		}

		switch (dataspace & HAL_DATASPACE_TRANSFER_MASK) {
		case HAL_DATASPACE_TRANSFER_LINEAR:
		return SkColorSpace::MakeRGB(SkNamedTransferFn::kLinear, gamut);
		@@ -264,7 +280,6 @@ sk_sp<SkColorSpace> DataSpaceToColorSpace(android_dataspace dataspace) {
		return SkColorSpace::MakeRGB(SkNamedTransferFn::kRec2020, gamut);
		case HAL_DATASPACE_TRANSFER_UNSPECIFIED:
		return nullptr;
		case HAL_DATASPACE_TRANSFER_HLG:
		default:
		ALOGV("Unsupported Gamma: %d", dataspace);
		return nullptr;
		@@ -381,5 +396,14 @@ skcms_TransferFunction GetPQSkTransferFunction(float sdr_white_level) {
		return fn;
		}

		// Skia skcms' default HLG maps encoded [0, 1] to linear [1, 12] in order to follow ARIB
		// but LinearEffect expects a decoded [0, 1] range instead to follow Rec 2100.
		std::optional<skcms_TransferFunction> GetHLGScaleTransferFunction() {
		std::optional<skcms_TransferFunction> hlgFn = {};
		skcms_TransferFunction_makeScaledHLGish(&hlgFn.value(), 1.f / 12.f, 2.f, 2.f, 1.f / 0.17883277f,
		0.28466892f, 0.55991073f);
		return hlgFn;
		}

		} // namespace uirenderer
		} // namespace android

libs/hwui/utils/Color.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -23,6 +23,8 @@
		#include <math.h>
		#include <system/graphics.h>

		#include <optional>

		struct ANativeWindow_Buffer;
		struct AHardwareBuffer_Desc;

		@@ -127,6 +129,7 @@ struct Lab {
		Lab sRGBToLab(SkColor color);
		SkColor LabToSRGB(const Lab& lab, SkAlpha alpha);
		skcms_TransferFunction GetPQSkTransferFunction(float sdr_white_level = 0.f);
		std::optional<skcms_TransferFunction> GetHLGScaleTransferFunction();

		} /* namespace uirenderer */
		} /* namespace android */